Two approaches to single-station detection and removal of ground roll from seismic reflection measurements by three component polarization analysis

Abstract

The ground roll consists, among others, of Rayleigh waves that are characterized by low velocity, high amplitude, low frequency and retrograde elliptical particle motion in the direction of propagation. The particle motion can be recorded by employing three-component seismic receivers that allow Rayleigh waves and body waves to be differentiated by their nature of polarization. From covariance analysis and eigendecomposition on a sliding time window polarization attributes are calculated to identify the state and direction of polarization in the data in a single station approach. The polarization attributes are then applied to the data in two polarization filters. The linearity method minimizes all non-linear arrivals in a multiplication method while the ellipticity method separates the elliptically polarized signal before subtracting it from the original data. Simulations of both polarization filters on synthetic and field data show that an accurate polarization analysis can be made to identify individual arrivals and suppress the ground roll to a great extent.